TRIPARTITE KEY SHARING SYSTEM, TRIPARTITE KEY SHARING METHOD, USER DEVICE, PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a tripartite key sharing technique ensuring security without assuming a random oracle that cannot be achieved using a real hash function.;SOLUTION: A secure tripartite key sharing system is achieved without assuming a random oracle, by using a pseudo-random function and a strong random extractor (or key derivation function) in place of a random oracle, and adding a mechanism for detecting an illegal ad hoc public key (method using CFZ encryption, or method using a non-interactive zero knowledge certification).;COPYRIGHT: (C)2014,JPO&INPIT